The archive.

The multiplier, in Keynes and Kahn, arrives as a timeless ratio linking investment to income; Machlup's 1939 intervention insists it can only be understood as a dated process. Public wages become shop receipts, which become factory receipts, which only later become incomes to be spent again — and between the rounds lie inventories, pay dates, and spending habits. He builds an 'income propagation period,' tentatively about three months, to measure how long expenditure takes to become income anew, and shows that a higher propensity to consume yields a larger eventual multiple but a longer road to it, so a government minding the coming fiscal year may collect only a fraction. Leakages, he adds, need not mean hoarding; saved funds may repay debt or buy securities, deferring rather than destroying the next round of spending.

For a discussion of time lags, transition phases, and other intertemporal relationships, Keynesian terminology is not well suited.

Does bank credit drive economic change, or can it merely accommodate movements in trade? In this short review of Valentin F. Wagner’s history of credit theories, Fritz Machlup singles out a selective rehabilitation of the Banking School: Wagner challenges its equation of bank notes with deposits while recovering its view that bank credit may substitute for trade credit without exerting an independent dynamic influence. Machlup’s sympathy for this reconsideration does not blunt his criticism of Wagner’s elaborate classifications, repetitions, and difficult terminology. The review offers a concise encounter with a disputed distinction in monetary theory—and with Machlup’s judgement of where historical scholarship can unsettle accepted doctrine without conclusively overturning it.

An exchange-rate change can increase export volumes while reducing receipts in foreign currency—and import expenditure can rise in one currency while falling in another. In this first installment of The Theory of Foreign Exchanges, Fritz Machlup uses such distinctions to connect currency markets with production, consumption, and competition. His central challenge is to explanations that treat national price levels as independently given determinants of exchange rates. By tracing how exporters win customers from competitors, how new goods become tradable, and how overseas payments redirect domestic spending, he shows why exchange rates can move without prior inflation or deflation. Readers gain a concrete way to distinguish accounting identities from behavioural responses, and genuine changes in trade from the effects of the currency used to measure them.

Does buying shares withdraw purchasing power from the market for goods and services? In this 1940 paper, Fritz Machlup challenges the idea that stock speculation necessarily absorbs funds during a boom. His distinctive move is to follow bank deposits rather than classify loans by borrower or collateral: the effect depends on where money came from, where it goes, and what it would otherwise have financed. Against Keynes’s account of speculative liquidity preference, he shows how bearish sellers could seek liquidity through interest-bearing call loans rather than idle cash. Readers can discover why heavy trading and large brokers’ loans do not by themselves establish monetary contraction—and why Machlup judged speculation’s net effect during the twenties’ boom probably inflationary, while allowing that hoarding and debt repayment could become deflationary in the downswing.

What can economic analysis establish about monopoly, and where must political judgment begin? In this 1942 review of E. A. G. Robinson’s Monopoly, Fritz Machlup admires the handbook’s integration of institutional detail and theory while testing the precision of its claims. He questions the basis for comparing one person’s satisfaction with another’s burden and identifies the constant-marginal-cost assumption needed for Robinson’s claim about demand elasticity and monopoly output. His appreciation is equally discriminating: breaking a monopoly into a few firms need not restore competition, and opportunities for firms to combine complicate equilibrium. The review offers a compact example of sympathetic criticism, showing how accessible applied economics can remain answerable to explicit assumptions and clearly acknowledged value judgments.

Expert testimony about inventions is not necessarily evidence of patents’ economic benefits. In this sharply critical review of George E. Folk’s Patents and Industrial Progress, Fritz Machlup asks what a defense of patent protection must establish beyond the convictions of engineers, businesspeople, and patent lawyers. He faults Folk’s extensive reproduction of favorable testimony for failing to explain effects on unemployment or living standards, and challenges a reassurance about competition in glass-container manufacturing. Yet Machlup leaves the merits of the patent system open: his objection is to advocacy presented as analysis, not to the policy defended. This short review offers a concrete test of where professional authority ends and economic reasoning must begin.

What I am opposed to is propaganda in the disguise of analysis. The book perhaps contains legal arguments, but it contains no economic analysis.

A market can have many sellers without being open to more. In Part I of Competition, Pliopoly and Profit, Fritz Machlup makes this distinction the starting point for examining whether profitable opportunities actually attract newcomers. His term “pliopoly” shifts attention from existing firms’ conduct to entry over time—and to the uncertainty, investment requirements and indivisible plants that can obstruct it. Crucially, the profits at stake are not simply those recorded in business accounts: ownership arrangements can disguise resource earnings as profits, while opportunity costs reveal what entry might eliminate. This first installment offers readers a precise way to distinguish persistent economic profit from scarcity rents, and to understand why rapid entry can coexist with slow withdrawal by loss-making firms.

'Forced saving' had wandered through monetary theory, cycle theory, war finance, socialism, rationing, and corporate boardrooms, collecting incompatible meanings along the way — and this 1943 survey sets out to disentangle them. At its core lies a monetary idea: when bank credit or newly active money finances investment, capital formation can exceed what people meant to save, forced on the community, in Machlup's phrase, through monetary witchcraft. But the real consequences vary wildly, from no added investment under immobility to genuine consumption sacrifice at full employment. Drawing on Robertson's careful separation of money 'lacking' from real deprivation, and on Mises, Schumpeter, and Keynes, he ends with a thirty-four-item taxonomy of synonyms and homonyms, deliberately retiring the ambiguous phrase itself. A term that connotes so many meanings, he concludes, has lost its usefulness.

Saving refers merely to money amounts; lacking, on the other hand, refers to “real” quantities.

First published in 1943 and reissued here, this technical study rebuilds foreign-trade theory around the money-income multiplier, discarding the instantaneous multiplier of textbook exposition for a period-by-period sequence in which time itself becomes a variable. Machlup traces how an autonomous export sets off successive rounds of income and induced imports, then layers in induced saving, foreign repercussions across two and three countries, and the capital account, all through numerical model tables and elementary algebra. Foreign trade, he shows, plays a double role—both multiplicand and determinant of the multiplier—so that imports lagging behind exports are what let income rise at all. He closes by refusing the neo-mercantilist temptation, since the multiplier offers no honest warrant for tariffs and quotas once price effects, retaliation, and the gains from international division of labor are admitted.

Only the lag of imports behind exports makes it possible that money income rises as a consequence of the exports.

Can competitive price theory be taught convincingly before students encounter monopoly and imperfect competition? In this 1943 review of the preliminary edition of George J. Stigler’s The Theory of Competitive Price, Fritz Machlup weighs that pedagogical choice while testing the precision of definitions, diagrams, and explanations. His detailed corrections coexist with admiration for Stigler’s concise exposition: a demanding textbook can clarify theory without making it easy. The review offers a concrete view of what Machlup expects from economic instruction—analytical distinctions that hold up under scrutiny, assumptions whose purpose students understand, and technical tools connected to actual problems. His closing disagreement with Schumpeter over the book’s level turns on students’ mathematical preparation, leading to an insistence that advanced theory belongs in the undergraduate curriculum.

Empirical critics of the 1940s claimed that interviews and questionnaires had caught firms behaving in ways marginal analysis could not explain; the reply here is that they had misunderstood the theory they meant to refute. Economic theory, Machlup argues, is essentially a theory of adjustment to change, and its variables are the entrepreneur's own expected costs and revenues, not the observer's accounting magnitudes — a driver overtaking a truck responds to speed and distance without computing them. Reports of 'full-cost' pricing dissolve on inspection: average cost may smooth fluctuations over time, discipline a cartel, or hint at rivals' demand elasticity without contradicting marginalism. He is hardest on Richard Lester's wage-employment surveys, whose 'importance' ratings confuse frequency with marginal effect. The theory has not been disproved, he insists, though better empirical work, grounded in theory, is badly needed.

The business man does what he does on the basis of what he thinks, regardless of whether you agree with him or not.

When Richard Lester marshalled questionnaire evidence to argue that businessmen do not think at the margin, Machlup answered with this compact 1947 reply, reprinted here, that concedes almost nothing. Lester’s executives said employment depends chiefly on sales and orders; Machlup responds that sales expectations were always part of marginal productivity reasoning, not an antimarginalist discovery. He works through Lester’s six conclusions on wage rates, variable costs, factor substitution, and multiprocess plants, insisting that marginal analysis never required rising unit costs and that firms can reckon in incremental rather than average terms. His deeper charge is that Lester mistakes the proximate vocabulary of managers — orders, morale, sales effort — for a refutation of the causal structure economists actually analyze.

Incremental costs and revenues can be known without any knowledge of average costs and revenues; the reverse is not true.